L-Carnitine occurs naturally in man, and exogenous L-carnitine is free from toxic effects at any therapeutic dose. L-carnitine appears to facilitate aerobic metabolism, probably by promoting the entry of pyruvate into the citric acid cycle as a result of lowering the ratio of acetyl-CoA to free CoA. This study is an attempt to confirm a report that patients with intermittent claudication have increased exercise capacity when L-carnitine is administered orally.